package edu.Test;

import java.util.Scanner;

public class test12 {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int[] a = new int[4];
        int t = 0;
        for (int i = 0; i < 4; i++) {
            a[i] = scan.nextInt();
            t += a[i];
        }
        if (t % 2 != 0) {
            System.out.println("NO");
        } else {
            int x = t / 2;
            if (a[0] + a[1] != x
                    && a[0] + a[2] != x
                    && a[0] + a[3] != x
                    && a[1] + a[2] != x
                    && a[1] + a[3] != x
                    && a[2] + a[3] != x
                    && a[0] != x && a[1] != x && a[2] != x && a[3] != x)
                System.out.println("NO");
            else {
                System.out.println("YES");
            }
        }
    }
}